support for MediaStreamTrack.getConstraints

src/MediaDevicesFake.test.ts

@@ -189,6 +189,7 @@ describe('attach device', () => {
  expect(track.readyState).toBe('live')
  expect(track.kind).toBe('video')
  })
+
  test('return audioinput with matching device id', async () => {
  fake.attach(anyMicrophone({ deviceId: 'not this one' }))
  fake.attach(anyMicrophone({ deviceId: 'attached', label: 'match' }))
@@ -203,6 +204,27 @@ describe('attach device', () => {
  expect(track.readyState).toBe('live')
  expect(track.kind).toBe('audio')
  })
+
+ test('provide access to the passed video constraints', async () => {
+ fake.attach(anyCamera())
+ const constraintInput = { facingMode: 'user' }
+ const stream = await fake.getUserMedia({ video: constraintInput })
+ const trackConstraints = stream.getTracks()[0].getConstraints()
+ expect(trackConstraints).toEqual({ facingMode: 'user' })
+ expect(trackConstraints).not.toBe(constraintInput)
+ })
+
+ test('replace true constraint with an empty object', async () => {
+ fake.attach(anyCamera())
+ const stream = await fake.getUserMedia({ video: true })
+ expect(stream.getTracks()[0].getConstraints()).toEqual({})
+ })
+
+ test('provide access to the passed audio constraints', async () => {
+ fake.attach(anyMicrophone())
+ const stream = await fake.getUserMedia({ audio: { noiseSuppression: true } })
+ expect(stream.getTracks()[0].getConstraints()).toEqual({ noiseSuppression: true })
+ })
  })
 
  describe('dispatch', () => {

src/MediaDevicesFake.ts

@@ -88,6 +88,8 @@ const trackConstraintsFrom = (
  throw new Error('with the current assumptions this should not happen')
 }
 
+const deepClone = (mediaTrackConstraints: MediaTrackConstraints) => JSON.parse(JSON.stringify(mediaTrackConstraints))
+
 const tryToOpenAStreamFor = (
  context: Context,
  deferred: Deferred<MediaStream>,
@@ -107,9 +109,10 @@ const tryToOpenAStreamFor = (
  context.notImplemented.call('should this be an over constrained error?')
  }
 
+ const constraintObject = typeof mediaTrackConstraints === 'boolean' ? {} : deepClone(mediaTrackConstraints)
  const mediaTrack = new MediaStreamTrackFake(
  context,
- initialMediaStreamTrackProperties(selectedDevice.label, trackKind),
+ initialMediaStreamTrackProperties(selectedDevice.label, trackKind, constraintObject),
  )
  openMediaTracks.track(selectedDevice, mediaTrack)
  mediaTrack.onTerminated = (track) => openMediaTracks.remove(track)

src/MediaStreamTrackFake.test.ts

@@ -8,7 +8,10 @@ describe('MediaStreamTrackFake', () => {
  let track: MediaStreamTrackFake
 
  beforeEach(() => {
- track = new MediaStreamTrackFake(defaultContext(), initialMediaStreamTrackProperties('The Label', anyTrackKind()))
+ track = new MediaStreamTrackFake(
+ defaultContext(),
+ initialMediaStreamTrackProperties('The Label', anyTrackKind(), {}),
+ )
  })
 
  test('enabled by default', () => {

src/MediaStreamTrackFake.ts

@@ -11,10 +11,15 @@ export interface MediaStreamTrackProperties {
  enabled: MediaStreamTrack['enabled']
  kind: TrackKind
  label: string
+ constraints: MediaTrackConstraints
 }
 
-export const initialMediaStreamTrackProperties = (label: string, kind: TrackKind): MediaStreamTrackProperties => {
- return { id: uuidV4(), readyState: 'live', enabled: true, kind, label }
+export const initialMediaStreamTrackProperties = (
+ label: string,
+ kind: TrackKind,
+ constraints: MediaTrackConstraints,
+): MediaStreamTrackProperties => {
+ return { id: uuidV4(), readyState: 'live', enabled: true, kind, label, constraints }
 }
 
 export type TrackTerminatedListener = (mediaStreamTrack: MediaStreamTrackFake) => void
@@ -175,7 +180,7 @@ export class MediaStreamTrackFake extends EventTarget implements MediaStreamTrac
  * Constraints can also specify ideal and/or acceptable sizes or ranges of sizes.
  */
  getConstraints(): MediaTrackConstraints {
- this._context.notImplemented.call('MediaStreamTrackFake.getConstraints()')
+ return this._properties.constraints
  }
 
  /**

src/MediaStreamTrackMother.ts

@@ -9,7 +9,7 @@ import {
 export const anyTrackKind = (): TrackKind => 'video'
 
 export const anyMediaStreamTrack = (overrides: Partial<MediaStreamTrackProperties> = {}) => {
- const initial = initialMediaStreamTrackProperties('stand in label', anyTrackKind())
+ const initial = initialMediaStreamTrackProperties('stand in label', anyTrackKind(), {})
  const properties = { ...initial, ...overrides }
  return new MediaStreamTrackFake(defaultContext(), properties)
 }